Environmental and Economic Performance of Hybrid Power-to-Liquid and Biomass-to-Liquid Fuel Production in the United States

Abstract

Power-to-liquids are a class of liquid drop-in fuels produced from electricity and carbon dioxide as the primary process inputs, which have the potential to reduce transportation’s climate impacts. We quantify the economic and life cycle environmental characteristics of four electrofuel technology pathways that rely on the Fischer–Tropsch synthesis but produce synthesis gas via different schemes: power-to-liquid (PtL) via electrolysis and a reverse water gas shift (RWGS) reaction; PtL via co-electrolysis; gasification of biomass-to-liquid (BtL); and a hybrid power- and biomass-to-liquid (PBtL) pathway. The results indicate that the hybrid PBtL pathway is the most environmentally and economically promising option for electrofuel production, with results highly dependent on input electricity source characteristics such as cost and emissions. The carbon intensities of electricity generation that must not be exceeded for electrofuels to have lower life cycle emissions than conventional diesel are 222, 116, and 143 gCO2e/kWh for PBtL, PtL electrolysis + RWGS, and PtL co-electrolysis, respectively. We characterize the PBtL pathway in more detail by combining spatially resolved data on biomass cultivation, electricity generation, and cost-optimized hydrogen production from renewable electricity in the United States (US). We find that the private emissions abatement cost for PBtL fuels varies between 740 and 2000 $/tCO2e, depending primarily on the location of fuel production.

Economic and Environmental Barriers of CO2-Based Fischer–Tropsch Electro-Diesel

“…Furthermore, many of these studies focus on economic performance, disregarding environmental impacts 8 − 13 or at most quantifying only the global warming potential while omitting other metrics. 14 − 17 …”

“…However, its performance on impacts beyond global warming remains unclear because they are often omitted. 14 − 17 This simplification is critical because electro-fuels may shift environmental burdens to other categories. Notably, this collateral damage has been observed in biomass-based synthetic fuels, 19 − 21 low-carbon power mixes, 22 , 23 carbon capture and utilization, 24 , 25 and FT electro-gasoline, 26 to mention a few.…”

“…Analyzing two electricity and three biogenic H 2 sources, they found that wind energy outperforms solar in carbon dioxide equivalent (CO 2 -eq) emissions, while a synergistic combination of both provides the best economic result. 17 Samavati et al studied a solid oxide electrolyzer cell (SOEC) implementing co-electrolysis coupled with biomass gasification. They concluded that this e-fuel is economically uncompetitive but can curb carbon emissions by 98−102%.…”

“…However, substantial literature is based on biomass, with only a few works considering using captured CO 2 and electrolytic H 2 as feedstock. Furthermore, many of these studies focus on economic performance, disregarding environmental impacts − or at most quantifying only the global warming potential while omitting other metrics. − …”

Techno-Economic Evaluation of Novel Hybrid Biomass and Electricity-Based Ethanol Fuel Production

“…Electrolytic hydrogen-supplemented biofuel production resulted in more cost-efficient production of biofuel compared to non-biomass synfuels (electrofuels) under a wide range of economic assumptions. Later Isaacs et al (2021) compared the economic and environmental performance of several electrofuel and hybrid biomass fuel pathways in the United States. They found the hybrid electricity-and biomass-based pathway to liquid fuels the most competitive and sustainable option.…”